As a side project, I took some orbital mechanics classes online via MIT and built a simulator for how bodies move through our solar system. I simulated a well-know asteroid, Apophis, and examined how much energy it would take to move it’s orbit relative to Earth. Such calculations are required for preventing a potential asteroid strike (though nothing as large as Apophis is likely to be both undetected and on a collision course with Earth) or solar-scale projects such as an Earth-Mars cycler.
